520 wiring swap

[littleredrider 409]

So I have a 90 520-8 speed, and have a 520H, think a 92 or 93, but either way has vacuum gauge, tach, amps and gas gauge. That tractor has a diesel on it, so don't need the gauges. So is it as simple as swapping the harness? Like an idiot I sold the engine harness with the bad motor, not sure if I can get it back. 

[lynnmor 7,727]

Just string the wires that you need, no need to have a bunch of wires that go nowhere.

[littleredrider 409]

guess should have worded it different. Want to put the vacuum and tach on the 520-8, they don't have any. They aren't being used on the donor, since it has the diesel. 

[lynnmor 7,727]

3 hours ago, littleredrider said:

guess should have worded it different. Want to put the vacuum and tach on the 520-8, they don't have any. They aren't being used on the donor, since it has the diesel. 

The tachometer connects to either of the two end terminals of the voltage regulator.  The vacuum gauge connects with a hose to a fitting in the intake manifold, that fitting will need to be added.

[cleat 7,177]

The signal source for the tach comes from the rearmost of the three terminals at the voltage regulator closest to the battery.

You can make it out in the picture below. the front terminal has a single white wire and the rear terminal has both a white wire and the grey tach wire connected to it.

Center terminal has the red battery connection wire on it.

 

 

You will see a raised boss on the top of the intake close to the carb as seen below. This is just in front of the carb.

 

 

You will need to drill and tap that to fit a 90 degree barbed fitting. Intake will need to be tapped to a tapered pipe thread I am unsure of the exact size but I would think 1/4"

 

 

The fitting points to the left as sitting on the tractor away from the muffler.

 

I believe it uses 1/4" vacuum line.

 

 

[littleredrider 409]

That sounds simple enough. But other than the tach, no addition wiring?